1# HiTraceId 2 3<!--Kit: Performance Analysis Kit--> 4<!--Subsystem: HiviewDFX--> 5<!--Owner: @qq_437963121--> 6<!--SE: @MontSaintMichel--> 7<!--TSE: @gcw_KuLfPSbe--> 8 9## Overview 10 11Defines a **HiTraceId** instance. 12 13**Since**: 12 14 15**Related module**: [Hitrace](capi-hitrace.md) 16 17**Header file**: [trace.h](capi-trace-h.md) 18 19## Summary 20 21### Member Variables 22 23A little-endian **HiTraceId** consists of the following fields in sequence: 24 25| Field| Number of Bits| Description| 26| -------- | -------- | -------- | 27| uint64_t valid | 1 | Whether a **HiTraceId** instance is valid.| 28| uint64_t ver | 3 | Version number of **HiTraceId**.| 29| uint64_t chainId | 60 | Chain ID of **HiTraceId**.| 30| uint64_t flags | 12 | Flag of **HiTraceId**.| 31| uint64_t spanId | 26 | Span ID of **HiTraceId**.| 32| uint64_t parentSpanId | 26 | Parent span ID of **HiTraceId**.| 33 34A big-endian **HiTraceId** consists of the following fields in sequence: 35 36| Field| Number of Bits| Description| 37| -------- | -------- | -------- | 38| uint64_t chainId | 60 | Chain ID of **HiTraceId**.| 39| uint64_t ver | 3 | Version number of **HiTraceId**.| 40| uint64_t valid | 1 | Whether a **HiTraceId** instance is valid.| 41| uint64_t parentSpanId | 26 | Parent span ID of **HiTraceId**.| 42| uint64_t spanId | 26 | Span ID of **HiTraceId**.| 43| uint64_t flags | 12 | Flag of **HiTraceId**.| 44